I decided on Monitor Audio for my music, but

for about $2500, I have two choices

Monitor Audio Silver S6 + REL Strata III subwoofer = about $2300


Monitor Audio Gold Refercence 20 without sub = about $2400

My music preferces is broad from classic to jazz to rock

what's the pros and cons for each?

what would you get?
Not to throw a monkey wrench into your search, but at $2500 there are more choices. An audition of the Von Schweikert VR-2s could prove worthwhile. I auditioned both the GR20 and GR60 in my system, nice speakers but I couldn't seem to warm up to them. I ended up going with VSA, the 4jr. I think I saw a used pair of VR-2s for $1500 in the classifieds and I know there has been plenty of threads. Best of luck.
The Ref3A De Capo is $2500 and, in my opinion, simply amazing.
Since this is a music system I'd say do without the sub and buy a full range speaker. Subs are for HT...
No need to look any further go with the gold ref20s they are beautiful speakers! I own a pair and could not be happier! I have also owned the S8 which was also very nice. This is another option and then spend the remaining $1000 on a nice CDP like the Jolida JD100A which I plan on purchasing in the near future. No need for the sub even in HT applications because the speakers have a very nice low end extension. The only time I would add the sub is if you have a really large room. Also if you decide to use them for HT I would purchase the matching center before the sub. Remember to use good cables, I use biwired Zu Cable "Wax" with mine and am very pleased. Also with any MA speaker allow it to burn in for up to 200 hours to fully appreciate the speaker. MA makes fantastic speakers that when set up properly can out compete many more expensive speakers. I wish there was more coverage of these speakers on Audiogon. Enjoy!
I have a pair of GR60 and am very happy with them.
For my music setup, I have the VonSchweikert VR4GenIIISE.
They're just two very different speakers.
My best advice for you is to try and listem to them before making any decision.
Good luck